De-noising algorithm for SNR improvement of underwater acoustic signals using CWT based on Fourier Transform

Underwater wireless communication is a prominent research
field owing to its vast range of applications such as under-
water sensor networks, remotely operated vehicles (ROVs)
and tsunami warning systems. The acoustic signals used in the underwater wireless systems are 105 times slower than light which makes it band-limited. Communication under water is affected not only by natural activities but also by shipping noises, all of which degrade the performance of underwater systems. Hence appropriate de-noising algo-
rithms have to be developed to improve the performance
of the band-limited underwater systems. The algorithm
described in this paper was developed using linear fre-
quency modulation (FM) waveform as input and using the
continuous wavelet transformation (CWT) based on fast
Fourier Transform (FFT) method with Morlet wavelet. The
proposed algorithm provides an SNR improvement of around 12 dB when compared with the algorithm developed using the chirp signal as input and using Morlet wavelet with wavelet packet decomposition (WPD) technique.